Abstract Condensation of ethyl 3-polyfluoroalkyl-3-oxopropionates with excess triethyl orthoformate gave ethyl 3-polyfluoroalkyl-2-ethoxymethylidene-3-oxopropionates which reacted with primary aliphatic, aromatic, and heterocyclic amines to form ethyl 2-alkyl (aryl, hetaryl) aminomethylidene-3-polyfluoroalkyl-3-oxopropionates. According to the X-ray diffraction and IR data, the latter exist in the crystalline state as the corresponding E ...